The less polar fractions of the latex of Euphorbia peplus were found to contain obtusifoliol, cycloartenol, 24-methylenecycloartanol, lanosterol, and 24-methylenelanosterol in the free and esterified triterpene alcohol fractions; 9-cis-tricosene as the major component of the hydrocarbon fraction; and a new acyclic triterpene alcohol named peplusol (1). The structure of 1 was determined as the R-isomer of (all-E)-2-(5,9-dimethyl-1-methylene-4,8-decadienyl)-5,9, 13-trimethyl-4,8,12-tetradecatrien-1-ol by spectral and chemical methods.